354 research outputs found
Dynamic Quantized Consensus of General Linear Multi-agent Systems under Denial-of-Service Attacks
In this paper, we study multi-agent consensus problems under
Denial-of-Service (DoS) attacks with data rate constraints. We first consider
the leaderless consensus problem and after that we briefly present the analysis
of leader-follower consensus. The dynamics of the agents take general forms
modeled as homogeneous linear time-invariant systems. In our analysis, we
derive lower bounds on the data rate for the multi-agent systems to achieve
leaderless and leader-follower consensus in the presence of DoS attacks, under
which the issue of overflow of quantizer is prevented. The main contribution of
the paper is the characterization of the trade-off between the tolerable DoS
attack levels for leaderless and leader-follower consensus and the required
data rates for the quantizers during the communication attempts among the
agents. To mitigate the influence of DoS attacks, we employ dynamic
quantization with zooming-in and zooming-out capabilities for avoiding
quantizer saturation
A Survey of Resilient Coordination for Cyber-Physical Systems Against Malicious Attacks
Cyber-physical systems (CPSs) facilitate the integration of physical entities
and cyber infrastructures through the utilization of pervasive computational
resources and communication units, leading to improved efficiency, automation,
and practical viability in both academia and industry. Due to its openness and
distributed characteristics, a critical issue prevalent in CPSs is to guarantee
resilience in presence of malicious attacks. This paper conducts a
comprehensive survey of recent advances on resilient coordination for CPSs.
Different from existing survey papers, we focus on the node injection attack
and propose a novel taxonomy according to the multi-layered framework of CPS.
Furthermore, miscellaneous resilient coordination problems are discussed in
this survey. Specifically, some preliminaries and the fundamental problem
settings are given at the beginning. Subsequently, based on a multi-layered
framework of CPSs, promising results of resilient consensus are classified and
reviewed from three perspectives: physical structure, communication mechanism,
and network topology. Next, two typical application scenarios, i.e.,
multi-robot systems and smart grids are exemplified to extend resilient
consensus to other coordination tasks. Particularly, we examine resilient
containment and resilient distributed optimization problems, both of which
demonstrate the applicability of resilient coordination approaches. Finally,
potential avenues are highlighted for future research.Comment: 35 pages, 7 figures, 5 table
Performance analysis with network-enhanced complexities: On fading measurements, event-triggered mechanisms, and cyber attacks
Copyright © 2014 Derui Ding et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Nowadays, the real-world systems are usually subject to various complexities such as parameter uncertainties, time-delays, and nonlinear disturbances. For networked systems, especially large-scale systems such as multiagent systems and systems over sensor networks, the complexities are inevitably enhanced in terms of their degrees or intensities because of the usage of the communication networks. Therefore, it would be interesting to (1) examine how this kind of network-enhanced complexities affects the control or filtering performance; and (2) develop some suitable approaches for controller/filter design problems. In this paper, we aim to survey some recent advances on the performance analysis and synthesis with three sorts of fashionable network-enhanced complexities, namely, fading measurements, event-triggered mechanisms, and attack behaviors of adversaries. First, these three kinds of complexities are introduced in detail according to their engineering backgrounds, dynamical characteristic, and modelling techniques. Then, the developments of the performance analysis and synthesis issues for various networked systems are systematically reviewed. Furthermore, some challenges are illustrated by using a thorough literature review and some possible future research directions are highlighted.This work was supported in part by the National Natural Science Foundation of China under Grants 61134009, 61329301, 61203139, 61374127, and 61374010, the Royal Society of the UK, and the Alexander von Humboldt Foundation of Germany
Analysis, filtering, and control for Takagi-Sugeno fuzzy models in networked systems
Copyright © 2015 Sunjie Zhang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.The fuzzy logic theory has been proven to be effective in dealing with various nonlinear systems and has a great success in industry applications. Among different kinds of models for fuzzy systems, the so-called Takagi-Sugeno (T-S) fuzzy model has been quite popular due to its convenient and simple dynamic structure as well as its capability of approximating any smooth nonlinear function to any specified accuracy within any compact set. In terms of such a model, the performance analysis and the design of controllers and filters play important roles in the research of fuzzy systems. In this paper, we aim to survey some recent advances on the T-S fuzzy control and filtering problems with various network-induced phenomena. The network-induced phenomena under consideration mainly include communication delays, packet dropouts, signal quantization, and randomly occurring uncertainties (ROUs). With such network-induced phenomena, the developments on T-S fuzzy control and filtering issues are reviewed in detail. In addition, some latest results on this topic are highlighted. In the end, conclusions are drawn and some possible future research directions are pointed out.This work was supported in part by the National Natural Science Foundation of China under Grants 61134009, 61329301, 11301118 and 61174136, the Natural Science Foundation of Jiangsu Province of China under Grant BK20130017, the Fundamental Research Funds for the Central Universities of China under Grant CUSF-DH-D-2013061, the Royal Society of the U.K., and the Alexander von Humboldt Foundation of Germany
Self-triggered Resilient Stabilization of Linear Systems with Quantized Output
This paper studies the problem of stabilizing a self-triggered control system
with quantized output. Employing a standard observer-based state feedback
control law, a self-triggering mechanism that dictates the next sampling time
based on quantized output is co-developed with an output encoding scheme. If,
in addition, the transmission protocols at the controller-to-actuator (C-A) and
sensor-to-controller (S-C) channels can be adapted, the self-triggered control
architecture can be considerably simplified, leveraging a delicate
observer-based deadbeat controller to eliminate the need for running the
controller in parallel at the encoder side. To account for denial-of-service
(DoS) in the S-C channel, the proposed output encoding and self-triggered
control schemes are further made resilient. It is shown that a linear
time-invariant system can be exponentially stabilized if some conditions on the
average DoS duration time are met. There is a trade-off between the maximum
inter-sampling time and the resilience against DoS attacks. Finally, a
numerical example is presented to demonstrate the practical merits of the
proposed self-triggered control schemes and associated theory
On Resilient Control of Nonlinear Systems under Denial-of-Service
We analyze and design a control strategy for nonlinear systems under
Denial-of-Service attacks. Based on an ISS-Lyapunov function analysis, we
provide a characterization of the maximal percentage of time during which
feedback information can be lost without resulting in the instability of the
system. Motivated by the presence of a digital channel we consider event-based
controllers for which a minimal inter-sampling time is explicitly
characterized.Comment: 7 pages, 1 figur
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